Cast-rolled aluminum alloy for water cooling plate and production process and application of cast-rolled aluminum alloy

Abstract

The invention relates to the technical field of aluminum alloy manufacturing, in particular to a cast-rolling aluminum alloy for a water-cooling plate and a production process and application of the cast-rolling aluminum alloy. The production process of the cast-rolled aluminum alloy for the water-cooled plate comprises the steps of smelting, refining, degassing and filtering, cast rolling, one-pass cold rolling, homogenizing annealing, cold rolling and finished product annealing. Wherein after smelting, molten aluminum is detected to comprise, by mass, 0.58%-0.60% of Si, 0.3%-0.37% of Fe, 1.45%-1.55% of Mn, 0.02%-0.03% of Mg, 0.54%-0.57% of Cu, 0.02%-0.03% of Ti and the balance Al, and the sum of Fe and Mn is smaller than or equal to 1.85%; and during homogenizing annealing, heat preservation is conducted for 16-18 h at the metal temperature of 560-580 DEG C. The cast-rolled aluminum alloy for the water-cooling plate, prepared by the production process, is not easy to crack after being stamped and has good mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy manufacturing, and in particular to a cast-rolled aluminum alloy for a water-cooling plate and a production process and application thereof. Background Art

[0002] The water cooling plate is an important heat dissipation device in new energy vehicles. Its function is to cool down the motor and battery of electric vehicles to ensure that they can work normally under high temperature conditions. It is beneficial to improve the performance of electric vehicles and extend the service life of motors and batteries. It plays an important role in the development and promotion of new energy vehicles.

[0003] Water-cooled plates need to be stamped during processing, so they have high requirements for the mechanical properties of the raw materials. Generally, the tensile strength is required to be ≥150MPa, the yield strength is ≥55MPa, and the elongation is ≥20%. At present, water-cooled plates are generally made of metal materials such as copper, aluminum alloy, and stainless steel. Usually, the performance of hot-rolled materials is better than that of cast-rolled materials. When aluminum alloys are used to prepare water-cooled plates, hot-rolled aluminum alloys are mostly used. However, the cost of hot-rolled materials is significantly higher than that of cast-rolled materials, and the conventional preparation method is to weigh the smelting raw materials, smelt, cast, anneal, and then obtain hot-rolled semi-finished products, and then use cold rolling mills for rolling, coiling, and annealing, which consumes high energy and may also result in coarse grains and excessive segregation accumulations, resulting in poor quality of finished products, especially the tensile strength, yield strength, or / and elongation not meeting the standards.

[0004] In order to reduce automobile production costs and improve the performance of water-cooled plate products, it is necessary to further develop and research the production process of aluminum alloy casting and rolling materials so that they can meet the mechanical property requirements of water-cooled plates. Summary of the invention

[0005] In view of the technical problem that the aluminum alloy produced by the existing casting and rolling method is difficult to meet the mechanical property requirements when stamping a water-cooled plate, the present invention provides a cast-rolled aluminum alloy for a water-cooled plate and its production process and application, improves the raw material ratio, optimizes the casting and rolling process, and the cast-rolled aluminum alloy for the water-cooled plate produced is not easy to crack after stamping and has good mechanical properties.

[0006] In a first aspect, the present invention provides a production process of a cast-rolled aluminum alloy for a water-cooled plate, comprising smelting, refining, degassing and filtering, casting and rolling, one-pass cold rolling, homogenization annealing, cold rolling and finished product annealing; Among them, the components and mass percentages of the aluminum liquid detected after smelting are: Si 0.58%-0.60%, Fe 0.3%-0.37%, Mn1.45%-1.55%, Mg 0.02%-0.03%, Cu 0.54%-0.57%, Ti 0.02%-0.03%, the balance is Al, and Fe+Mn≤1.85% is satisfied; During refining, refining agent + nitrogen injection refining is used; During degassing and filtration, the refined aluminum liquid is added with a grain refiner before entering the online degassing device for grain refinement. The added amount is 2.2kg / tAl, and the hydrogen content of the online degassing is ≤0.12ml / 100gAl. Then it is filtered through a double filter plate; During one pass of cold rolling, the rolling oil temperature is 36-39°C; During homogenization annealing, keep the metal temperature at 560-580℃ for 16-18h; During cold rolling, the rolling oil temperature is 37-38°C and the finished product thickness is controlled between 1.0-1.5mm.

[0007] Furthermore, the components and mass percentages of the aluminum liquid after smelting are: Si 0.591%, Fe 0.335%, Mn 1.482%, Mg 0.026%, Cu 0.556%, Ti 0.027%, and the balance is Al.

[0008] Furthermore, the refining temperature is controlled at 730-750°C, and the refining tube moves evenly at the bottom of the furnace for 12 minutes without any dead corners.

[0009] Furthermore, the grain refiner is titanium wire.

[0010] Furthermore, the pore sizes of the double filter plates are 40ppi and 50ppi.

[0011] Furthermore, during casting and rolling, the temperature of the aluminum liquid in the front box was controlled to be 688-692°C, the casting and rolling speed was 780mm / min, and the thickness of the cast and rolled billet was 7.0mm.

[0012] Furthermore, during homogenization annealing, the metal temperature was kept at 580°C for 18 hours.

[0013] Furthermore, during annealing of the finished product, the metal temperature was kept at 405°C for 2 hours.

[0014] In a second aspect, the present invention provides a cast-rolled aluminum alloy for a water-cooled plate, which is prepared according to the production process of the cast-rolled aluminum alloy for a water-cooled plate.

[0015] In a third aspect, the present invention provides use of the above-mentioned cast-rolled aluminum alloy for water-cooling plates in the preparation of water-cooling plates.

[0016] The beneficial effects of the present invention are: In the field of aluminum alloy water-cooled plate processing, composition and grains are crucial to the internal structure and stamping performance of the finished product. The present invention provides a production process for cast-rolled aluminum alloy for water-cooled plates, and the composition ratio range is precisely and reasonably controlled. For example, by controlling the Fe+Mn≤1.85% in the components, the formation of segregation aggregates can be avoided, and it is not easy to crack during stamping; adding a certain amount of Mg and Ti can promote grain refinement. In the specific production process, by adding a certain amount of grain refiner, it is ensured that the first-level cast-rolled grain size can be obtained; by controlling the oxygen content of online degassing and the filter aperture of the filter plate, a fully clean aluminum liquid is obtained to avoid slag in the melt, and to prevent the presence of slag and hydrogen from affecting the stamping forming performance and surface quality of the water-cooled plate; after a cold rolling, the uniform heating at a certain temperature can improve the problem of coarse grains caused by direct homogenization of the coil, and can avoid other problems caused by the inhomogeneity of the cast structure on the upper and lower surfaces of the coil to the homogenization annealing, and fully eliminate the component segregation and structural inhomogeneity of the cast structure. The cast-rolled aluminum alloy for the water-cooling plate obtained by the present invention has a tensile strength of 155 MPa, a yield strength of 67 MPa, an elongation of 27.4%, no cracking after stamping operation, and has great market potential. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0018] Example 1 The production process of cast-rolled aluminum alloy for water-cooled plates includes the following steps: (1) Melting: The raw materials are put into the melting furnace for melting, and the composition is tested after being stirred evenly. The composition and mass percentage of the aluminum liquid are: Si 0.591%, Fe 0.335%, Mn 1.482%, Mg 0.026%, Cu 0.556%, Ti 0.027%, and the balance is Al, and Fe+Mn≤1.85%; (2) Refining: The refining temperature is controlled within the range of 730-750°C. The refining tube is evenly moved at the bottom of the furnace for 12 minutes without any dead corners. Refining agent + nitrogen injection is used; (3) Degassing and filtration: Before the refined aluminum liquid enters the online degassing device, titanium wire is added for grain refinement. The added amount is 2.2kg / tAl. The hydrogen content of online degassing is ≤0.12ml / 100gAl. Then it is filtered through a double filter plate of 40ppi and 50ppi. Samples are taken at the head and tail of the material for grain detection; (4) Casting and rolling: The filtered aluminum liquid enters the front box for casting. The temperature of the aluminum liquid in the front box is controlled within the range of 688-692°C, the casting and rolling speed is 780mm / min, and the thickness of the cast and rolling billet is 7.0mm; (5) One-pass cold rolling: rolling the cast billet into a coil with a thickness of 4.5 mm, and the rolling oil temperature is 36 °C; (6) Homogenization annealing: The coil is subjected to homogenization annealing at a metal temperature of 580°C for 18 hours to make the composition and structure more uniform and improve the stamping capacity of the finished product; (7) Cold rolling: The coil after homogenization annealing is cold rolled again, the rolling oil temperature is 38°C, and the finished product thickness is controlled between 1.0-1.5mm; (8) Finished product annealing: Keep the metal temperature at 405°C for 2 hours.

[0019] After testing, the tensile strength of the cast-rolled aluminum alloy for water-cooled plates was 155MPa, the yield strength was 67MPa, the elongation was 27.4%, and there was no cracking after the stamping operation.

[0020] Comparative Example 1 The production process of cast-rolled aluminum alloy for water-cooled plates includes the following steps: (1) Melting: The raw materials are melted in a smelting furnace, stirred evenly and then tested for composition. The composition and mass percentage of the molten aluminum are: Si 0.592%, Fe 0.332%, Mn 1.483%, Mg 0.023%, Cu 0.0212%, Ti 0.022%, the remainder is Al, and Fe+Mn≤1.85% is satisfied; (2)-(8) are the same as Example 1, except that the rolling oil temperature of the cold rolling in (5) is 38°C; and the rolling oil temperature of the cold rolling in (7) is 37°C.

[0021] After testing, the tensile strength of the cast-rolled aluminum alloy for water-cooled plates is 128MPa, the yield strength is 65MPa, and the elongation is 30%. Its compressive strength is low and cannot meet the mechanical performance requirements required by product development. Technical personnel analyzed that this result was caused by its low Cu content.

[0022] Comparative Example 2 The production process of cast-rolled aluminum alloy for water-cooled plates includes the following steps: (1) Melting: The raw materials are put into the melting furnace for melting, and the composition is tested after being stirred evenly. The composition and mass percentage of the aluminum liquid are: Si 0.588%, Fe 0.329%, Mn 1.473%, Mg 0.025%, Cu 0.552%, Ti 0.024%, and the balance is Al, and Fe+Mn≤1.85%; (2)-(8) are the same as Example 1, except that (5) the rolling oil temperature of the cold rolling is 39°C; and (6) the homogenization annealing is carried out at a metal temperature of 500°C for 12 hours.

[0023] After testing, the tensile strength of the cast-rolled aluminum alloy for water-cooled plates was 152MPa, the yield strength was 65MPa, and the elongation was 22%. There were problems such as coarse grains, center segregation, and orange peel. In addition, the aluminum ash on the surface was heavy after rolling, which did not meet the stamping requirements. The technicians analyzed that the result was caused by the low homogenization annealing temperature of 500℃.

[0024] Comparative Example 3 The production process of cast-rolled aluminum alloy for water-cooled plates includes the following steps: (1) Melting: The raw materials are put into the melting furnace for melting, and the composition is tested after being stirred evenly. The composition and mass percentage of the aluminum liquid are: Si 0.591%, Fe 0.335%, Mn 1.482%, Mg 0.026%, Cu 0.0212%, Ti 0.027%, and the balance is Al, and Fe+Mn≤1.85%; (2)-(8) are the same as in Example 1.

[0025] According to tests, the tensile strength of the cast-rolled aluminum alloy used for water-cooled plates is 132MPa, the yield strength is 66MPa, and the elongation is 28%. Its compressive strength is low and cannot meet the mechanical performance requirements required for product development.

[0026] Comparative Example 4 The production process of cast-rolled aluminum alloy for water-cooled plates includes the following steps: (1)-(8) are the same as Example 1, except that (6) homogenization annealing is carried out at a metal temperature of 500°C for 12 hours.

[0027] After testing, the tensile strength of the cast-rolled aluminum alloy used for water-cooled plates was 153MPa, the yield strength was 65MPa, and the elongation was 23%. Problems such as coarse grains, center segregation, and orange peel appeared. In addition, the aluminum ash on the surface was heavy after rolling, which did not meet the stamping requirements.

[0028] Comparative Example 5 The production process of cast-rolled aluminum alloy for water-cooled plates includes the following steps: (1) Melting: The raw materials are put into the melting furnace for melting, and the composition is tested after being stirred evenly. The composition and mass percentage of the aluminum liquid are: Si 0.591%, Fe 0.335%, Mn 1.482%, Mg 0.001%, Cu 0.0212%, Ti 0.001%, and the balance is Al, and Fe+Mn≤1.85%; (2)-(8) are the same as in Example 1.

[0029] After testing, the tensile strength of the cast-rolled aluminum alloy used for water-cooled plates was 148MPa, the yield strength was 65MPa, and the elongation was 24%. Problems such as coarse grains, center segregation, and orange peel appeared, and the tensile strength was low, which did not meet the stamping requirements.

[0030] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily conceive of changes or substitutions within the technical scope disclosed by the present invention, and such changes or substitutions shall be within the scope of protection of the present invention.

Claims

1. A production process of cast-rolled aluminum alloy for water-cooled plates, characterized in that: Including smelting, refining, degassing and filtering, casting and rolling, one-pass cold rolling, homogenization annealing, cold rolling and finished product annealing; Among them, the components and mass percentages of the aluminum liquid detected after smelting are: Si 0.58%-0.60%, Fe 0.3%-0.37%, Mn1.45%-1.55%, Mg 0.02%-0.03%, Cu 0.54%-0.57%, Ti 0.02%-0.03%, the balance is Al, and Fe+Mn≤1.85% is satisfied; During refining, refining agent + nitrogen injection refining is used; During degassing and filtration, the refined aluminum liquid is added with a grain refiner before entering the online degassing device for grain refinement. The added amount is 2.2kg / tAl, and the hydrogen content of the online degassing is ≤0.12ml / 100gAl. Then it is filtered through a double filter plate; During one cold rolling, the rolling oil temperature is 36-39℃; During homogenization annealing, keep the metal temperature at 560-580℃ for 16-18h; During cold rolling, the rolling oil temperature is 37-38°C and the finished product thickness is controlled between 1.0-1.5mm.

2. The production process of cast-rolled aluminum alloy for water-cooled plate according to claim 1, characterized in that: The components and mass percentages of the aluminum liquid after smelting are: Si 0.591%, Fe 0.335%, Mn 1.482%, Mg 0.026%, Cu 0.556%, Ti 0.027%, and the balance is Al.

3. The production process of cast-rolled aluminum alloy for water-cooled plate according to claim 1, characterized in that: The refining temperature is controlled at 730-750℃, and the refining tube moves evenly at the bottom of the furnace for 12 minutes without any dead corners.

4. The production process of cast-rolled aluminum alloy for water-cooled plate according to claim 1, characterized in that: The grain refiner is titanium wire.

5. The production process of cast-rolled aluminum alloy for water-cooled plate according to claim 1, characterized in that: The dual filter plates filter at pore sizes of 40ppi and 50ppi.

6. The production process of cast-rolled aluminum alloy for water-cooled plate according to claim 1, characterized in that: During casting and rolling, the temperature of the aluminum liquid in the front box was controlled at 688-692℃, the casting and rolling speed was 780mm / min, and the thickness of the cast and rolled billet was 7.0mm.

7. The production process of cast-rolled aluminum alloy for water-cooled plate according to claim 1, characterized in that: During homogenization annealing, the metal temperature is kept at 580°C for 18 hours.

8. The production process of cast-rolled aluminum alloy for water-cooled plate according to claim 1, characterized in that: When annealing the finished product, keep the metal temperature at 405℃ for 2h.

9. A cast-rolled aluminum alloy for a water-cooled plate, characterized in that: It is prepared according to the production process of cast-rolled aluminum alloy for water-cooling plates as described in any one of claims 1 to 8.

10. Use of the cast-rolled aluminum alloy for water-cooling plates according to claim 9 in the preparation of water-cooling plates.